Chemical sample analyzers may be employed to measure the content of a particular element or compound (constituent) in a sample (e.g., specimen). Throughout this description, it will be understood by those skilled in the art that the term constituent element may be used to refer to an analyte, element, compound, component and/or any substance in the sample. Some chemical sample analyzers may be adapted to measure the content of carbon, sulfur, nitrogen, among others, of a sample. Carbon analyzers may be employed to measure the total organic carbon (TOC), the inorganic carbon (IC), the total carbon (TC; TC=TOC+IC), purgeable organic carbon (POC) and/or non-purgeable organic carbon (NPOC) content of the sample. TOC measurement processes may include oxidizing organic carbon in the sample, detecting and quantifying the oxidized carbon (e.g., CO2) and presenting the result in units of mass of carbon per volume of the sample.
Carbon analyzers are used in a variety of industries to measure, monitor and analyze analytical information relating to the carbon content of a given sample. Measuring the carbon content in liquids such as drinking water, treated or untreated wastewater and ultra pure water for pharmaceutical or clean room applications is a routine way to assess the purity of the liquid sample. Monitoring the carbon content of wastewater is particularly significant in the chemical, pharmaceutical, semiconductor, food and beverage industries. Other areas that require careful monitoring of carbon content include the paint, resin and coating industries. Carbon analysis also can be essential for ascertaining whether drinking water, groundwater, soils and wastewater comply with government regulations. Carbon analysis also may be performed to protect process equipment such as boilers, turbines and purification devices because organic materials such as carbon may contaminate the process equipment.
Furthermore, there is an increasing interest in measuring, monitoring and analyzing carbon levels in solids or semi-solid specimens such as soils, clays and sediments. Accordingly, these solids or semi-solids can be measured, monitored and analyzed for carbon content using known analyzer accessories.
Nitrogen analyzers may be employed to measure the nitrogen content in the sample. Nitrogen in a sample may be converted to nitric oxide (NO). The NO is mixed with ozone to form NO2*(NO2 in excited state). When the NO2* returns to its ground state it gives off energy in the form of light. This process is known as chemiluminescence. The amount of light given off is proportional to the amount of NO in the sample.
Conventional sample analyzers employ a flow-through type detector technique to measure the content of a particular constituent in a sample. Flow-through technology provides a certain level of sensitivity in the measured content. There is a need for a sample analyzer to measure the content of a constituent in a gas sample with increased sensitivity over the conventional flow-through type detector techniques.